A Jamaican-born poet and novelist, Dallas's fictional works included Percival, or Nature Vindicated (1801), Aubrey (1804), The Morelands. Tales Illustrative of the Simple and Surprising (1805), The Knights: Tales Illustrative of the Marvellous (1808), and Sir Francis Darrell; Or the Vortex (1820). He also published a volume of poems, two dramas, and some polemical works. He had a connection for some years with Byron, and his Recollections of the Life of Lord Byron from the year 1808 to the end of 1814 (1825) was published posthumously.